High-pressure steam generator



July 3, 1945. L. E. SEBALD I HIGH PRESSURE STEAM GENERATOR Filed June 7, 1939 4 Shee is-Sheet 1 007457 l/VZET ATTORNEYS L. E. SEBALD HIGH PRESSURE STEAM GENERATOR Filed June 7. 1939 4 Sheets-Sheet 2 Julyfi 1945.

2 z; ATTORNEYS y 1.. ISEBALEI) 3 9 HIGH PRESSURE STEAM GENERATOR Filed June 7, 1939 4 Sheets-Sheet s Q YINVENTOR ATTORNEYS July 3, 1945. SEBALD 2,379,661

HIGH PRESSURE STEAM GENERATOR Filed June 7, 1539 .4 Sheets-Sheet 4 2/ 5 20 J 4 r 5; lg E r; a6

Z17 E M 8 w Lig ATTORNEYS Patented July 3, 1945 HIGH-PRESSURE STEAM GENERATOR Leslie E. Sebald, Ridgewood, N. 1., assignor to The rlscom-Russell Company, New York, N. Y., a

corporation of Delaware Application June 7, 1939, Serial No. 271,185

5 Claims. (Cl. 122-32) This invention relates to high pressure steam generators indirectly heatedby a circulating medium of hot fluid. Ihe objects of the invention are to provide a durable, eflicient boiler in which all possibility of cross-leaks between the heating and heated'fluids is eliminated, in which the occurrence andrepair of leaks in the separate circulating systems will be substantially minimized, in which extreme temperatures and pressure maybe safely used without danger and without subjecting the structure to the stresses of differential expansion. Important additional objects are to provide an evaporator structure readily adaptabale to varying conditions, particularly in the temperature of the heating fluid and the amount of heat to be extracted therefrom.

Broadly,' I attain these objects by employing wholly independent circulating systems for the heating and heated fluids and by efiecting the necessary transfer of heat from one to the other solely by metallic conduction without at any point enclosing one circulating vessel within the other. I

Specifically, I have solved these problems in a particularly effective embodiment of my invention, by employing the heat exchanging units disclosed in Letters Patent No. 2,013,187, granted September 3, 1935, to Price. 'The use of this device as an. element of a steam generator in the combination hereinafter described and claimed permits the solution not only of the diflicultiesinherent in all previous indirectly heated boilers of which I am aware, but also of certain difficulties inherent in water tube boilers generally.

In the accompanying drawings I have shown a preferred embodiment of my invention designed primarily as a waste heat boiler and temperature regulator for the hot fluid salt used as the heat absorbing medium for exothermic catalytic reactions. Other embodiments of my invention employing means for attaining its objects as broadly herebefore suggested may be used without departing from the scope and spirit thereof.

Fig. 1 is a transverse vertical section through a steam generator embodying my invention, taken on the line il Fig.2;

Fig.2 is a side elevation of a steam generator embodying my invention;

Fig. 3 is a longitudinal vertical section of a steam generator embodying my invention;

Fig. 4. is a transverse. vertical section of my invention showing the generator installed in .a supporting and insulating tower; I

Fig. 5 is a horizontal section taken through line 5-5 0! Fig. 4;

Fig- 6 is a transverse vertical section of the upper and lower headers 01 the heat exchanging portions of the generator installed in a supporting tower; a

Fig. 7 is a longitudinal vertical section of the upper and lower headers of the heat exchanging portions of the. generator installed in a supporting tower;

Fig. 8 is a horizontal section taken on 8-8 of Fig. 6';

Fig. 9 is a schematic diagram showing a system of circulation of the heating and heated fluids;

Fig. 10 is a schematic diagram showing a modifled system of circulation; and

Fig; 11 is a schematic diagram showing another the line modified system of circulation.

In this embodiment oi'my invention the heating fluid is introduced by the inlet manifold I and pipes across the clean-out header'B into the outgoing connecting pipes 1 up through the opposite heat exchanging units 4, around a second return bend 6, down again through the opposite heat exchanging units t andoutlet connectin pipes 2 out the outlet manifold l2. The heated fluid, in this instance water, is fed through the steam drum l3 and'maintained at a level indicated by the water line shown in Figs. 1 and 3. This fluid passes through the downcomers [4 into the mud drum l5 and thence out by the paired upcomer pipes i6 into the opposite heat exchan ing units 4. It is there flashed into steam and discharged through the paired connecting pipes l'l into the steam drum it behind the baflles I8.

The heat exchanging units 4 embodying the inventlon of the Price patent hereinbelore mentioned, as clearly shown in Fig. 5 and, in somewhat more detail, in Fig. -8, consist of two heating tubes 28 and two heated tubes 26 nested together by and expanded into the close packed perforated metal member 20. .These members serve to conduct theheat from the tubes containing the heating fluid to the tubes containing the heated fluid, and to reinforce the tubes greatly against extreme pressures. It will be particularly observed pansion arise in the heat exchanging p rtions of this boiler. All the tubes connecting'the drums and manifolds with the heat exchanging portions of this generator have wide compensation bends 9 so that any differential expansion between the drum and manifold supports and the connecting tubes is amply taken care of. The circulation of heating and heated fluids provided in this embodiment of my invention is straight-line, inherently free from burbles and dead pockets, resulting in uniform heat transfer throughout the evaporating portion of the system.

The steam drum of this generator is provided with the usual boiler accessories, e. g., feedwater regulator, gauge glass connections, safety valve and clean-out connections, feed-water circulator and heater, and other appurtenances not a part of this invention. Similarly the heating fluid circulating system is provided with cleanout plates and positive circulator means not a part of this invention.

A vertical steam generator of the type illustrated is preferably supported by an insulated tower 23 of structural steel as shown in Figs. 4 and 5. At the lower part of the framework 24 of the tower 23, the salt manifolds 8 and I2, and the mud drum l are rigidly attached. The lower headers 3' of the heat exchanging units 4 are supported by and between blocks attached to the vertical tower members 36.

The heat exchanging units 4, comprising two heating tubes 26 and two heated tubes 25 structurally united by closely packed metal members 20, act as supporting columns to maintain the weight of the steam drum i3, its various attachments and its insulation 22. This whole steam drum assembly is rigidly attached to the upper platform 2|. This platform 2|, in turn, is supported by the blocks 35 attached to it and resting on the upper headers 5 of the heat exchanging units 4. When the whole unit is at atmospheric temperature not in operation, this platform 2| does not bear on the tower frame 24, but is vertically clear therefrom and is maintained in its proper position horizontally bythe guide members 30 thereof.

Thus the. platform 2| constitutes a floating frame supported by the heat exchanging units 4, but guided in its vertical movements bythe tower structure 24, bearing with it the steam drum l3 and insulating cap' 32. This whole assembly is free to rise and fall with variations in 'empe'rature, particularly in any starting and stopping of operations, according to the ex- Pension and contraction of the heat exchan ing units 4. The compensation bends Ill in the downcomers I4 relieve any stress of differential expansion therein.

The use of the manifolds i, 8, and i2 in the heating circuit, of the steam and mud drums t3 and I6, and particularly of the feed water dis tributor 33inslde the steam drum I3 maintains a substantial uniformity of temperature between, the various heat exchanging units .4. Thus all parts of this device are protected from the strains of differential expansion by my invention, and in particular the difllculties of of a jacket are avoided.

Figs. 6 and 'I show details of construction in headers and 6 of the heat exchanging units 4. At the upper headers 6 the salt pipes 25within1 the heat-exchanging units are connected by the return bend 6, which is removably held in place by the clamp yoke 21. At the lower headers 3 the pipes 25 are connected with the salt inlet,

outlet, and clean-out headers as hereinbefore.

described by connecting pipes 2 and I, and are expanded into the header 3 in grooved holes.

These holes, extending through the header 3, are tapped on opposite sides thereof by the pipes 2 and 1, and are sealed at their lower ends by the plugs 29 removably held in place by the clamp yoke 28.- By removing the return bend Band plugs 29 the salt tubes25 are opened up for easy cleanout.

At the upper headers 5, the water tubes 26, expanded into grooves in the header, extend through it to a welded connection with the steam drum connecting tubes At thelower headers 3 the water tubes 26, expanded into grooves in the header, extend through it to a welded connection with the mud drum connecting tubes l6.

Essentially, the headers 3 and 5 are specialized thick members permitting the hereinbefore 'indicated attachments and connections, but also serving as heat conducting means exactly as do the thinner closely packed members-20 in which the tubes 25 and 26 are also expanded as shown in Fig. 8.

In Fig. 9 is shown schematically the circulating system of the heating fluid which I have already described in connection with the embodiment of my invention selected for the purpose of illustration in Figs. 1-8. In it the hot circulating fluid must pass four times in the heating 'tubes 3| and 32 in paths parallel to the steaming tubes 26 in its passage from the intake manifold I to the outlet manifold 12. This cir culating system I have termed the series syssealing tubing in its passage through the walls tern. Without making any alteration in the heated circulation and with only simple alterations in the heating structure the modified circulating systems shown in Figs. 10 and 11 may be achieved.

In Fig. 10 I show a schematic heating fluid circulating system which I have termed seriesparallel. In it the hot circulating fluid must pass twice in the heating tubes 3| and 32 in paths parallel to the steaming tubes 26 in its passage from the intake manifold to the outietmanifold I2. As can be readily understood, this change is accomplished by connecting the inlet header I with the heating fluid upcomers 3| in both opposed banks of heat exchanging units, by connecting the outlet header I2 by means of the return bends 6 to the heatin'g'fiuid downcomers 32, and omitting entirely the intermediate cleanout manifold 8.

In Fig. 11 I show a schematic heating fluid circulating system which I have termed parallel. In it the hot circulating fluid must pass once in the heating tubes 25 in a path parallel to the steaming tubes 26 in itspassage from the intake manifold 'l to the outlet manifold l2. In this arrangement I omit the return bends Gjand elevate the inlet manifold i above the opposed banks of heat exchanging units. I connect all the salt pipes .25 to this manifold at their top and to the outlet manifold l2 at the bottom. This construction is possible with slight alteration in the structure-i. e., so placing the compensation bends ll) of the water downcomers M as to leave place for the elevated inlet manifold I, remov-.

ual installations. This flexibility provided by my invention permits a high salvage value of a generator constructed according to my invention in the event that a user dismantles any particular installation of it.

Water tube boilers, whether heated by flue gases or by other circulating hot fluids, e. g. mercury vapor, in shells or jackets, present several problems which are solved by my invention. The source of these problems is lack of uniformity of flow of the heating fluid past the water tubes. This results in inequality of heat transfer in the various tubes, often in serious hot and cold spots, with attendant strain and inefficiency. The prior art is crowded with attempts to solve this problem, chiefly by baflles designed in various ways to equalize the flow. This solution of the problem introduces its own difficultythe burbles and congestions attendant on changes of flow direction.

My invention, by use of straight-line positive circulation insures absolute uniformity of flow readily adjustable as to rate to insure the optimum heat transfer in each installation. The use as a limitation of my invention. It isobvious that without departing from the spirit or scope of my invention other specific forms of indirect steam generators employing wholl independent circulating systems for the vaporizing and vaporized fluids, effecting the necessary heat transfer by metallic conduction without any point enclosing one circulating vessel within the other,

1. A water tube boiler heated bya hot fluid circulating medium comprising a steam drum, a mud drum, downcomer tubes descending from said steam drum to said mud drum, steaming tubes'rising from said mud drum to said steam drum, a heating medium intake manifold, a heat ing medium outlet manifold, tubes for circulating the heating medium from saidintake manifold to said outlet manifold, and metal members structurally connecting said heating tubes with said steaming tubes for a portion of their respective lengths and transferring heat from said heating tubes to said steaming tubes, said downconier tubes, heating tubes, and steaming tubes being separately provided with means .for reliev ing expansion stresses therein.

7 2. A vertical Water tube boiler heated by a hot fluid circulating medium comprising a heating medium intake manifold, return bends, heating medium tubes rising thereto from said intake manifold, a cleanout manifold, heating medium tubes descending thereto from said return bends, additional return bends, heating medium tubes rising thereto from said cleanout manifold, a heating medium outlet manifold,'heating medium tubes descending thereto from said additional return bends, a mud drum, a steam drum, steaming tubes rising from said mud drum to said steam drum, a multiplicity of metal heat conducting member having four parallel perforations in each member, the heating medium tubes rising to and descending from each return bend being paired and nested with and structurally connected to a pair of said steaming tubes for a portion of their respective lengths by passing through the four perforations of a plurality of said metal heat conducting members, said heating medium tubes and steaming tubes when nested being parallel and vertical, and downcomer tubes descending from said steam drum to said muddrum, all the aforementioned tubes being separately provided with expansion bends and all of the aforementioned tubes, drums, or manifolds being wholly external to any other of said tubes, drums or manifolds.

3. In a water tube boiler according to claim 1, a supporting structure comprising a framework, the mud drum, intake and outlet manifolds being attached thereto and the lower end of the structurally connected portions of the heating and steaming tu-bes abutting thereon, and a platform, the steam drum being attached thereto, said platform abutting on the upper ends of said structurally connected portions of the heating and steaming tubes and being mounted on saidframework slidable in the direction of the expansion of said portions of the heating and steaming tubes.

4. In a water tube boiler according to claim 1, a supporting structure comprising a framework extending to the tops of the structurally connected portions of the heating and steaming tubes, a boiler insulating shell co-extensive therewith and mounted thereon, the mud drum, intake and outlet manifolds being attached to and the lower ends of the aforementioned portions of the heating and steaming tubes abutting on said framework, a platform, the steam drum being attached thereto, said platform abutting on the aforementioned portions of the heating and steaming tubes and being mounted on said framework slidable inthe direction of the expansion of said portions of the heating and steaming tubes, and a boiler insulating cap mounted on and extending below said platform, overlapping the aforementionedinsulating shell in closely'spaced relation to the outside surface thereof to a greater distance than the maximum expansion of the aforementioned structurally connected portion of the heating and steaming tubes.

5. In a water tube boiler heated by a 17 fl d circulating medium, vertical water tubes, a drum being connected to the tops thereof for collecting the steam therefrom and means for supplying water thereto being connected to the bottoms thereof, independent vertical tubes for circulating the heating medium, said tubes for circulating the heating medium and said water tubes being mutually wholly external, metal heat conducting means structurally connecting said tubes for circulating the heating medium with said Water tubes for the major portion of their respective lengths, and a supporting means comprising foundation structure for supporting the ing on said structurally connected portions and mounted on said tower structure slidable in the direction of the expansion ofsaid tubes.

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